partition seating depth

[stew]

I have typically used speer bullets and found them rather easy to find a good shooting load. It was suggested to try some partitions and am trying them in a few different guns, right now the 210 in 338 win mag and the 160s in a 7mm mag so far not finding any thing that great. Was also recommended try try RL 19 and 22 and again nothing working that great. So far imr 7828 and imr 4831 is working best in the 338 with the 225 speer and 210 swift. So my main question right now is with Partition bullets what kind of seating depth (jump) do they seem to like. I understand every gun can be different.
Thanks for your time

 

[DrMike]

Welcome aboard, Stew; glad to have you here. Treat Partitions as you would any cup-and-core bullet. Whatever jump you've allowed for the Speers will likely work with the Partition. I've always seated my bullets with about a 0.010 inch jump to the lands.

 

[Elkman]

Welcome to this forum, undoubtedly one of the best on the net. My 7 mm likes H-4350 with the 160 PT, 60 or 61 works well. Can't give you my seating depth as am am not home. Many here have some great loads for the .338. Good luck with them both.

 

[SJB358]

Welcome aboard, Stew; glad to have you here. Treat Partitions as you would any cup-and-core bullet. Whatever jump you've allowed for the Speers will likely work with the Partition. I've always seated my bullets with about a 0.010 inch jump to the lands.

I usually start at about .025" off but Mikes done way more of this than me. I typically end up about .035-.050 with my PTs.

I've done real well with the 210's in the past. They do tend to want a good kick in the rear before they come around for me though.

 

[DrMike]

Just reviewing my notes on the 7RM. I note that with 160 grain Fail Safes, 64 or 66 grains of RL22 gave me sub-MOA (I still have a large supply of these bullets that I've continued to use over the years). Seventy-one grains of N560 gave me good accuracy with SIE 160 grain HPBT. With 160 grain AccuBonds, 68 grains of RL25 yield sub-MOA accuracy and good velocity. Shooting 160 grain TSX, I used 67.5 grains of IMR7828 or 68 grains of RL25 for sub-MOA groups. Using 59.5 grains of H100V, I achieved 0.5 MOA with 160 grain Partitions. The 7 RM is not a particularly difficult cartridge to get to deliver good to fine accuracy.

I admit that I have done a lot more with the 175s than with the 160s. For many years, my "go to" load was built around 175 grain TBBC charged with 60.2 grains of WXR (or 79 grains of H870). Yeah, many years ago I laid in a good supply of H870 and WXR together with 175 grain TBBC just so I could continue to work with these loads. With the 175 grain Partition, I have several sub-MOA loads built with Magnum and with RL22.

Scotty definitely has greater experience with the 338WM.

 

[stew]

Thanks for the info guys, got out today to try abit more but just took the 338.
The other day when tried it was .015 off with the 210 partitions. I had all ready loaded up some others before I asked questions on here so tried the RL19 again and loaded 2 each at 72, 73, and 74 grains and tried 2 as well with IMR 4831 all at .020 off. The 4831 was not good the other 3 pairs varied from 3/4 to 1 1/8 and all pairs were vertical so think will try one more set of the 3 but a little deeper.

 

[SJB358]

Thanks for the info guys, got out today to try abit more but just took the 338.
The other day when tried it was .015 off with the 210 partitions. I had all ready loaded up some others before I asked questions on here so tried the RL19 again and loaded 2 each at 72, 73, and 74 grains and tried 2 as well with IMR 4831 all at .020 off. The 4831 was not good the other 3 pairs varied from 3/4 to 1 1/8 and all pairs were vertical so think will try one more set of the 3 but a little deeper.

RL19 is all over for different lots. Do you have the ability to check the speeds? I've seen better results around 76-77 grains in my components than lower charges.

 

[stew]

Thanks for the info guys, got out today to try abit more but just took the 338.
The other day when tried it was .015 off with the 210 partitions. I had all ready loaded up some others before I asked questions on here so tried the RL19 again and loaded 2 each at 72, 73, and 74 grains and tried 2 as well with IMR 4831 all at .020 off. The 4831 was not good the other 3 pairs varied from 3/4 to 1 1/8 and all pairs were vertical so think will try one more set of the 3 but a little deeper.

RL19 is all over for different lots. Do you have the ability to check the speeds? I've seen better results around 76-77 grains in my components than lower charges.

No sorry I don't, is there another powder you would recommend trying with the 210 partitions. I also have Imr 7828, Imr 4831, H4350 and RL 22 could possible find some others but pretty slim pickings here. The IMR 4831 worked not to bad with the 210 swift scirocco 11s.
I could also try the RL 19 at a higher charge .
Thanks

 

[SJB358]

I would try bumping up .5 grains at a time. Only you can tell what is safe in your rifle but even Noslers data shows 76 grains of 19. I like 19 a lot in the 338. I've been very successful with it using 200-250's. My current 210 load uses 19.

I think if you keep the same seating depth and continue upwards you should see your groups tighten up. Once you've found the powder charge you like small seating depth changes should get you where you want to be.

Can you post pictures of your current groups? Sometimes it's easier to assist if we can see what you've got going on.

 

[stew]

I would try bumping up .5 grains at a time. Only you can tell what is safe in your rifle but even Noslers data shows 76 grains of 19. I like 19 a lot in the 338. I've been very successful with it using 200-250's. My current 210 load uses 19.

I think if you keep the same seating depth and continue upwards you should see your groups tighten up. Once you've found the powder charge you like small seating depth changes should get you where you want to be.

Can you post pictures of your current groups? Sometimes it's easier to assist if we can see what you've got going on.

Not much of a computer guy I can send pictures to e-mails if that worked but don't no how to post them on sites.

 

[SJB358]

Sent you a PM.

 

[SJB358]

It's hard to say with two shots a piece but I'd keep pushing up to 76 barring any signs of pressure. Everything looks even and you may see them come together.

 

[stew]

Ya the only reason did 2 shot groups was hoping there was something that really jumped out either good or bad like the 2 from the 4831. Will Try some .5 increases up to 76 and see what it shows.

 

[stew]

Did some up to 75.5gr which was the best 2 shot group so far.

Also have some 140,150 and 160 gr in .284 caliber to try in the 7mm-08 , 280 and 7mm mag
Tried a few loads of the 150s in the 280 today 2 sets with imr 4831 and 2 sets with h4350.
The H4350 groups were better with the shot group at 47 gr in the same hole so will try a 3 and 5 shot group now to see.
so far I find the partitions a bit more finicky then the speers.

 

[preacher]

I always load for a hunting rifle, which means I "start" at .025" off the lands. I may end up out to .100 before its over, but if your cases are concentric after forming, a big jump to the lands are no problem, "usually". ha. I liked H4350 in the short powder column of the 338 win Mag myself. I also only loaded the 185XLC and the 210 XBT. So adjust accordingly. The 338WM is a "wonderful" cartridge for handloaders, so don't get discouraged, just keep experimenting! Good luck to you Pard!

 

[stew]

I always load for a hunting rifle, which means I "start" at .025" off the lands. I may end up out to .100 before its over, but if your cases are concentric after forming, a big jump to the lands are no problem, "usually". ha. I liked H4350 in the short powder column of the 338 win Mag myself. I also only loaded the 185XLC and the 210 XBT. So adjust accordingly. The 338WM is a "wonderful" cartridge for handloaders, so don't get discouraged, just keep experimenting! Good luck to you Pard!

I may have made my last post confusing. Im using the H4350 in the 280.
Trying RL 19 in the 338 with the 210 partitions.
Maybe Im being to fussy as well for can get the 3 shot groups down to 11/8 of an inch
Thanks for your input, maybe have to look at some H4350 loads for the 338 as well.

 

[preacher]

Well, I had a bad experience with R19 in the 338WM and the 185XLC. I had worked the load up around 55deg and when I tried it at 10deg I got patterns and lost 200+fps! I pulled the loads and they were caked, had to use a screwdriver to dig it out. I went to H4350, worked up a Manual load and killed my cow elk at 250yds! so, for me, no R19 in magnums, ha.

 

[SJB358]

Did some up to 75.5gr which was the best 2 shot group so far.

Also have some 140,150 and 160 gr in .284 caliber to try in the 7mm-08 , 280 and 7mm mag
Tried a few loads of the 150s in the 280 today 2 sets with imr 4831 and 2 sets with h4350.
The H4350 groups were better with the shot group at 47 gr in the same hole so will try a 3 and 5 shot group now to see.
so far I find the partitions a bit more finicky then the speers.

Here's the target. Apologize for taking so long.

 

[stew]

Did some up to 75.5gr which was the best 2 shot group so far.

Also have some 140,150 and 160 gr in .284 caliber to try in the 7mm-08 , 280 and 7mm mag
Tried a few loads of the 150s in the 280 today 2 sets with imr 4831 and 2 sets with h4350.
The H4350 groups were better with the shot group at 47 gr in the same hole so will try a 3 and 5 shot group now to see.
so far I find the partitions a bit more finicky then the speers.

Here's the target. Apologize for taking so long.

No worrys didn't expect you to have to put it up just wondered if any thoughts think will try some 3 shot groups at the 75.5 and possible the 74.
Thanks

 

[SJB358]

I would probably keep pushing upwards to 76/77 grains. I'd bet your around 2850'ish right now. Seems like your doing well. Might as well see what happens.